简介:Inphasefieldfracturemodelsthevalueoftheorderparameterdistinguishesbetweenbrokenandundamagedmaterial.Atcrackfacestheorderparameterinterpolatessmoothlybetweenthesetwostatesofthematerial,whichcanberegardedasphases.Thecrackevolutionfollowsimplicitlyfromthetimeintegrationofanevolutionequationoftheorderparameter,whichiscoupledtothemechanicalfieldequations.Amongotherphenomenaphasefieldfracturemodelsareabletoreproducecracknucleationininitiallysoundmaterials.Fora1Dsettingithasbeenshownthatcracknucleationistriggeredbythelossofstabilityoftheunfractured,spatiallyhomogeneoussolution,andthatthestabilitypointdependsonthesizeoftheconsideredstructure.Thisworknumericallyinvestigatestowhichextendsizeeffectsarereproducedbythe2Dphasefieldmodel.Exemplarily,afiniteelementstudyoftheholesizeeffectisperformedandthesimulationresultsarecomparedtoexperimentaldata.
简介:MagnesiumalloyEZ10(Mg-RE-Zn)wasdeformedintensionattemperaturesfrom20upto520°C.Arapiddecreaseoftheyieldandtensilestrengthwithtemperaturewasobservedattemperatureshigherthan300°C.Ontheotherhand,ductilityofsamplesrapidlyincreasedinthesametemperaturerange.Lightmicroscopyandscanningelectronmicroscopywasusedtorevealthereasonforthesebehaviours.Intermetallicparticlesingrainboundariesareresponsibleforexcellentmechanicalpropertiesatlowertemperatures.Diffusionalprocessesoccurringattemperatureshigherthan300°Csignificantlyinfluencedthedeformationmechanismaswellasthefracturecharacter.
简介:ThedistributedopticalfibersensingtechnologywasusedtoinvestigatethefracturebehavioroftheEpoxyAsphaltMixture.Thespatialdistributionandvariationofthestraindevelopmentwithcrackpropagationwereacquiredusingthebrillouinopticaltime-domainreflectometerthroughtheloadingexperimentsofthecompositebeamstructure.Inaddition,afiniteelementmodelofthecompositebeamstructurewasdevelopedtoanalyzethemechanicalresponsesoftheepoxyasphaltmixtureusingtheextendedfiniteelementmethod.Theexperimentalresultsshowthatthedevelopmentofcrackpropagationbecomesinstablewiththeincreaseoftheload,andlargerloadswillgeneratedeepercracks.Moreover,thenumericalresultsshowthatthemechanicalresponseofthecracktipchangeswiththecrackpropagation,andtheworstareasthatsubjectedtocrackdamagearelocatedonbothsidesofthecompositebeamstructure.
简介:骨头接枝可以被需要用metaphyseal在老病人填满骨头缺点弄碎的远侧的半径骨折。在这回顾,nonrandomized,单个外科医生的学习,我们评估了与使矿物化的骨胶原(MC)使用两块背面的锁住板与或没有扩大的临床、放射线学的结果为老病人与的骨头接枝背面地,metaphyseal弄碎半径破裂。在组1的病人(n=12)在组2用MC骨头接枝申请与背面的锁住的盘子被对待进metaphyseal骨头缺点,和那些(n=12)仅仅与背面的锁住的盘子。临床、放射线学的参数在外科以后在三和12个月被决定。在最后的后续,没有重要差别在2个组之间被注意以手掌倾斜并且光线的倾斜(p=0.80);然而,尺骨的变化在没有扩大,2与背面的锁住的盘子对待的组显著地增加了(p<0.05)。机能上地,这些组之间没有重要差别。我们的初步的学习建议骨头接枝代用品和背面的锁住盘子可以是的MC的那联合一为有metaphyseal的老病人有用地其他弄碎的远侧的半径骨折。